Help with CSC

Visa, MasterCard Discover

The Card Security Code (CSC) is a 3-digit security code
that is printed on the back of your Visa or MasterCard. The number
appears on the signature strip after the last four digits of your
account number.

The signature strip may contain your entire account
number or just the last four digits of your account number. Either way,
the CSC will appear after the last four digits of your account number.

The CSC is used to verify that you have possession of
the credit card you are attempting to use.

American Express

The Card Security Code (CSC) is a 4 digit, non-embossed number printed above your account number on the face of your card.